U.S. patent number 7,372,616 [Application Number 11/139,391] was granted by the patent office on 2008-05-13 for complex microdevices and apparatus and methods for fabricating such devices.
This patent grant is currently assigned to Microfabrica, Inc.. Invention is credited to Christopher A. Bang, Adam L. Cohen, John D. Evans, Michael S. Lockard.
United States Patent |
7,372,616 |
Bang , et al. |
May 13, 2008 |
Complex microdevices and apparatus and methods for fabricating such
devices
Abstract
Various embodiments of the invention are directed to various
microdevices including sensors, actuators, valves, scanning
mirrors, accelerometers, switches, and the like. In some
embodiments the devices are formed via electrochemical fabrication
(EFAB.TM.).
Inventors: |
Bang; Christopher A. (San
Diego, CA), Cohen; Adam L. (Los Angeles, CA), Lockard;
Michael S. (Lake Elizabeth, CA), Evans; John D.
(Arlington, VA) |
Assignee: |
Microfabrica, Inc. (Van Nuys,
CA)
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Family
ID: |
35148880 |
Appl.
No.: |
11/139,391 |
Filed: |
May 27, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050221529 A1 |
Oct 6, 2005 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10313795 |
Dec 6, 2002 |
7185542 |
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60429484 |
Nov 26, 2002 |
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60429483 |
Nov 26, 2002 |
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60422982 |
Nov 1, 2002 |
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60422007 |
Oct 29, 2002 |
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60392531 |
Jun 27, 2002 |
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60415374 |
Oct 1, 2002 |
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60379184 |
May 7, 2002 |
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60430809 |
Dec 3, 2002 |
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60379182 |
May 7, 2002 |
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60379135 |
May 7, 2002 |
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60415371 |
Oct 1, 2002 |
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60379133 |
May 7, 2002 |
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60340372 |
Dec 6, 2001 |
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60364261 |
Mar 13, 2002 |
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Current U.S.
Class: |
359/291; 205/71;
359/295; 438/738; 438/717; 205/116 |
Current CPC
Class: |
B81C
1/0019 (20130101); B33Y 10/00 (20141201); C25D
1/003 (20130101); H02N 1/008 (20130101) |
Current International
Class: |
G02B
26/00 (20060101); C25D 1/00 (20060101); H01L
21/00 (20060101); C25D 7/00 (20060101) |
Field of
Search: |
;359/291,295
;438/717,738 ;205/71,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Cohen, et al., "EFAB: Batch Production of Functional, Fully-Dense
Metal Parts with Micron-Scale Features", Proc. 9th Solid Freeform
Fabrication, The University of Texas at Austin, Aug. 1998, pp. 161.
cited by other .
Adam L. Cohen, et al., "EFAB: Rapid, Low-Cost Desktop
Micromachining of High Aspect Ratio True 3-D MEMS", Proc. 12th IEEE
Micro Electro Mechanical Systems Workshop, IEEE, Jan. 17-21, 1999,
pp. 244-251. cited by other .
"Microfabrication--Rapid Prototyping's Killer Application", Rapid
Prototyping Report, CAD/CAM Publishing, Inc., Jun. 1999, pp. 1-5.
cited by other .
Adam L. Cohen, "3-D Micromachining by Electrochemical Fabrication",
Micromachine Devices, Mar. 1999, pp. 6-7. cited by other .
Gang Zhang, et al., "EFAB: Rapid Desktop Manufacturing of True 3-D
Microstructures", Proc. 2nd International Conference on Integrated
MicroNanotechnology for Space Applications, The Aerospace Co., Apr.
1999. cited by other .
F. Tseng, et al., "EFAB: High Aspect Ratio, Arbitrary 3-D Metal
Microstructures Using a Low-Cost Automated Batch Process", 3rd
International Workshop on High Aspect Ratio Microstructure
Technology (HARMST'99), Jun. 1999. cited by other .
Adam L. Cohen, et al., "EFAB: Low-Cost, Automated Electrochemical
Batch Fabrication of Arbitrary 3-D Microstructures", Micromachining
and Microfabrication Process Technology, SPIE 1999 Symposium on
Micromachining and Microfabrication, Sep. 1999. cited by other
.
F. Tseng, et al., "EFAB: High Aspect Ratio, Arbitrary 3-D Metal
Microstructures Using a Low-Cost Automated Batch Process", MEMS
Symposium, ASME 1999 International Mechanical Engineering Congress
and Exposition, Nov. 1999. cited by other .
Adam L. Cohen, "Electrochemical Fabrication (EFABTM)", Chapter 19
of the MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press,
2002, pp. 19/1-19/23. cited by other.
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Primary Examiner: Kwok; Helen
Attorney, Agent or Firm: Smalley; Dennis R.
Parent Case Text
RELATED APPLICATIONS
This application is a continuation of U.S. Non-Provisional Patent
Application No. 10/313,795 filed on Dec. 6, 2002 now U.S. Pat. No.
7,185,546 which in turn claims benefit to U.S. Provisional Patent
Application Nos.: 60/364,261 filed on Mar. 13, 2002; 60/340,372
filed on Dec. 6, 2001; 60/379,133 filed on May 7, 2002; 60/415,371
filed on Oct. 1, 2002; 60/379,135 filed on May 7, 2002; 60/379,182
filed on May 7, 2002; 60/430,809 filed on Dec. 3, 2002; 60/379,184
filed on May 7, 2002; 60/415,374 25-A filed on Oct. 1, 2002;
60/392,531 filed on Jun. 27, 2002; 60/422,007 filed on Oct. 29,
2002; 60/422,982 filed on Nov. 1, 2002; 60/429,483 filed on Nov.
26, 2002; 60/429,484 filed on Nov. 26, 2002. Each of these
applications is incorporated herein by reference as if set forth in
full. U.S. patent application Ser. Nos. 60/379,177, filed on May 7,
2002, 60/379,130 filed on May 7, 2002, and 10/309,521, filed Dec.
3, 2002 are also incorporated herein by reference.
Claims
We claim:
1. A process for forming a multilayer microdevice, comprising: (a)
forming a layer comprising at least two materials on a substrate
that may include one or more previously deposited layers, each
comprising at least two materials, wherein one of the at least two
materials is a structural material and another of the at least two
materials is a sacrificial material; (b) repeating the forming
operation of "(a)" one or more times to form at least one
subsequent layer, comprising at least two materials on at least one
previously formed layer to build up a three-dimensional structure
from a plurality layers; wherein the forming of at least a plurity
of layers, comprises: (1) supplying a substrate; (2) supplying a
mask on a surface of the substrate having a desired pattern of
openings through which a first material of the at least two
materials can be effectively deposited or etched to yield a desired
pattern of the first material; (3) depositing the first material
within the openings or etching the first material from the
openings; (4) removing the mask; (5) depositing a second material
of the at least two materials to fill the void in the deposited
material; and (6) planarizing the deposited first and second
materials to provide a planarized layer; and (c) after formation of
the plurality of layers removing the sacrificial material from the
deposited structural material, to reveal the three-dimensional
structure, wherein the microdevice includes a 3D tilt mirror.
2. The process of claim 1 wherein the depositing of the first
material comprises electrodepositing the first material and the
depositing of the second material comprises electrodepositing the
second material.
3. The microdevice of claim 2 wherein the first and second
deposited materials are metals.
4. The microdevice of claim 3 wherein the microdevice comprises a
structure of overall dimension less than 1 centimeter with at least
some design features having dimensions smaller than 500
microns.
5. The microdevice of claim 4 wherein at least some of the design
features are smaller the 100 microns.
6. The microdevice of claim 5 wherein at least some of the design
features are smaller than 25 microns.
7. The microdevice of claim 3 wherein the mirror comprises a
rotatable structure with a reflective surface that is supported by
at least one spring-like structure, wherein the spring-like
structure is formed from the same material as that which forms the
reflective surface.
8. The microdevice of claim 7 where the mirror can rotate around a
first axis and about a second axis that is substantially
perpendicular to the first axis, wherein the first axis is defined
by first and second rod-like elements which produce a return force
when twisted, wherein the first and second rod-like elements are
supported by a loop shaped structure, which loop shaped structure
is in turn supported by third and fourth rod-like elements which
produce a return force when twisted, wherein the first and second
rod-like elements are substantially co-linear along a first line
and the third and fourth rod-like elements are substantially
co-linear along a second line where-in the first and second lines
are substantially perpendicular to one another.
9. The microdevice of claim 8 wherein the rotatable structure with
the reflective surface has thickness dimension that is at least in
part substantially thicker than the thickness dimension of the
first and second rod-like elements, wherein portions of the
rotatable structure may be thinner than a maximum thickness of the
rotatable structure such that the moment of inertia of the
rotatable structure is reduced.
10. The microdevice of claim 9 wherein the loop shaped structure
has a thickness dimension that is substantially thicker than the
thickness dimension of the third and forth rod-like elements.
11. The microdevice of claim 9 wherein the loop shaped structure
has thickness dimension that is substantially thicker than the
thickness dimension of the first and second rod-like elements.
12. The microdevice of claim 9 wherein the mirror is caused to
rotate by activation of one or more of a plurality of electrodes
located between the mirror and a substrate, wherein at least a
plurality of the electrodes are separated from the substrate.
13. The microdevice of claim 12 wherein a parasitic capacitance of
a circuit comprising the electrodes and the substrate is reduced
from what the parasitic capacitance would have been if the
electrodes were formed on the substrate.
14. The microdevice of claim 3 wherein the mirror is caused to
rotate by activation of one or more of a plurity of electrodes
located between a dielectric substrate and the mirror where each of
the plurity of electrodes is formed from a plurality of layers with
the configuration of structural material forming each electrode on
each layer configured to provided closer proximity to the mirror
when in an undeflected state in regions where tilting is less and
further seperation in regions where the mirror tilts further during
deflection such that the electrodes provide enhanced driving force
without obstructing movement of the mirror.
15. The microdevice of claim 3 wherein a plane of a reflective
surface of the mirror as formed is coincident with a boundary level
of one of the layers.
Description
FIELD OF THE INVENTION
The present invention relates generally to the field of miniature
devices while specific embodiments are directed to various sensors,
various actuators, valves, structures possessing complex fluid flow
paths, tooling, electrical devices, as well as other devices,
apparatus for producing complex miniature devices, and methods for
producing complex miniature devices. In some embodiments,
fabrication of devices occur via Electrochemical Fabrication
techniques that may involve the formation of a plurality of layers
of material formed and adhered to one another via one or more of
selective and/or blanket depositions (e.g. by electroplating),
selective and/or blanket etching (e.g. by chemical or
electrochemical processes), planarization and/or polishing, and/or
other forms of deposition.
BACKGROUND OF THE INVENTION
A technique for forming three-dimensional structures/devices from a
plurality of adhered layers was invented by Adam L. Cohen and is
known as Electrochemical Fabrication. It is being commercially
pursued by MEMGen.TM. Corporation of Burbank, Calif. under the
tradename EFAB.TM.. This technique was described in U.S. Pat. No.
6,027,630, issued on Feb. 22, 2000. This electrochemical deposition
technique allows the selective deposition of a material using a
unique masking technique that involves the use of a mask that
includes patterned conformable material on a support structure that
is independent of the substrate onto which plating will occur. When
desiring to perform an electrodeposition using the mask, the
conformable portion of the mask is brought into contact with a
substrate while in the presence of a plating solution such that the
contact of the conformable portion of the mask to the substrate
inhibits deposition at selected locations. For convenience, these
masks might be generically called conformable contact masks; the
masking technique may be generically called a conformable contact
mask plating process. More specifically, in the terminology of
MEMGen.TM. Corporation of Burbank, Calif. such masks have come to
be known as INSTANT MASKS.TM. and the process known as INSTANT
MASKING.TM. or INSTANT MASK.TM. plating. Selective depositions
using conformable contact mask plating may be used to form single
layers of material or may be used to form multi-layer structures.
The teachings of the '630 patent are hereby incorporated herein by
reference as if set forth in full herein. Since the filing of the
patent application that led to the above noted patent, various
papers about conformable contact mask plating (i.e. INSTANT
MASKING) and electrochemical fabrication have been published: 1. A.
Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will,
"EFAB: Batch production of functional, fully-dense metal parts with
micro-scale features", Proc. 9th Solid Freeform Fabrication, The
University of Texas at Austin, p161, August 1998. 2. A. Cohen, G.
Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will; "EFAB: Rapid,
Low-Cost Desktop Micromachining of High Aspect Ratio True 3-D
MEMS", Proc. 12th IEEE Micro Electro Mechanical Systems Workshop,
IEEE, p244, January 1999. 3. A. Cohen, "3-D Micromachining by
Electrochemical Fabrication", Micromachine Devices, March 1999. 4.
G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P. Will,
"EFAB: Rapid Desktop Manufacturing of True 3-D Microstructures",
Proc. 2nd International Conference on Integrated
MicroNanotechnology for Space Applications, The Aerospace Co.,
April 1999. 5. F. Tseng, U. Frodis, G. Zhang, A. Cohen, F.
Mansfeld, and P. Will, "EFAB: High Aspect Ratio, Arbitrary 3-D
Metal Microstructures using a Low-Cost Automated Batch Process",
3rd International Workshop on High Aspect Ratio MicroStructure
Technology (HARMST'99), June 1999. 6. A. Cohen, U. Frodis, F.
Tseng, G. Zhang, F. Mansfeld, and P. Will, "EFAB: Low-Cost,
Automated Electrochemical Batch Fabrication of Arbitrary 3-D
Microstructures", Micromachining and Microfabrication Process
Technology, SPIE 1999 Symposium on Micromachining and
Microfabrication, September 1999. 7. F. Tseng, G. Zhang, U. Frodis,
A. Cohen, F. Mansfeld, and P. Will, "EFAB: High Aspect Ratio,
Arbitrary 3-D Metal Microstructures using a Low-Cost Automated
Batch Process", MEMS Symposium, ASME 1999 International Mechanical
Engineering Congress and Exposition, November, 1999. 8. A. Cohen,
"Electrochemical Fabrication (EFABTM)", Chapter 19 of The MEMS
Handbook, edited by Mohamed Gad-El-Hak, CRC Press, 2002. 9.
"Microfabrication - Rapid Prototyping's Killer Application", pages
1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June
1999.
The disclosures of these nine publications are hereby incorporated
herein by reference as if set forth in full herein.
The electrochemical deposition process may be carried out in a
number of different ways as set forth in the above patent and
publications. In one form, this process involves the execution of
three separate operations during the formation of each layer of the
structure that is to be formed: 1. Selectively depositing at least
one material by electrodeposition upon one or more desired regions
of a substrate. 2. Then, blanket depositing at least one additional
material by electrodeposition so that the additional deposit covers
both the regions that were previously selectively deposited onto,
and the regions of the substrate that did not receive any
previously applied selective depositions. 3. Finally, planarizing
the materials deposited during the first and second operations to
produce a smoothed surface of a first layer of desired thickness
having at least one region containing the at least one material and
at least one region containing at least the one additional
material.
After formation of the first layer, one or more additional layers
may be formed adjacent to the immediately preceding layer and
adhered to the smoothed surface of that preceding layer. These
additional layers are formed by repeating the first through third
operations one or more times wherein the formation of each
subsequent layer treats the previously formed layers and the
initial substrate as a new and thickening substrate.
Once the formation of all layers has been completed, at least a
portion of at least one of the materials deposited is generally
removed by an etching process to expose or release the
three-dimensional structure that was intended to be formed.
The preferred method of performing the selective electrodeposition
involved in the first operation is by conformable contact mask
plating. In this type of plating, one or more conformable contact
(CC) masks are first formed. The CC masks include a support
structure onto which a patterned conformable dielectric material is
adhered or formed. The conformable material for each mask is shaped
in accordance with a particular cross-section of material to be
plated. At least one CC mask is needed for each unique
cross-sectional pattern that is to be plated.
The support for a CC mask is typically a plate-like structure
formed of a metal that is to be selectively electroplated and from
which material to be plated will be dissolved. In this typical
approach, the support will act as an anode in an electroplating
process. In an alternative approach, the support may instead be a
porous or otherwise perforated material through which deposition
material will pass during an electroplating operation on its way
from a distal anode to a deposition surface. In either approach, it
is possible for CC masks to share a common support, i.e. the
patterns of conformable dielectric material for plating multiple
layers of material may be located in different areas of a single
support structure. When a single support structure contains
multiple plating patterns, the entire structure is referred to as
the CC mask while the individual plating masks may be referred to
as "submasks". In the present application such a distinction will
be made only when relevant to a specific point being made.
In preparation for performing the selective deposition of the first
operation, the conformable portion of the CC mask is placed in
registration with and pressed against a selected portion of the
substrate (or onto a previously formed layer or onto a previously
deposited portion of a layer) on which deposition is to occur. The
pressing together of the CC mask and substrate occur in such a way
that all openings, in the conformable portions of the CC mask
contain plating solution. The conformable material of the CC mask
that contacts the substrate acts as a barrier to electrodeposition
while the openings in the CC mask that are filled with
electroplating solution act as pathways for transferring material
from an anode (e.g. the CC mask support) to the non-contacted
portions of the substrate (which act as a cathode during the
plating operation) when an appropriate potential and/or current are
supplied.
An example of a CC mask and CC mask plating are shown in FIGS.
1A-1C. FIG. 1A shows a side view of a CC mask 8 consisting of a
conformable or deformable (e.g. elastomeric) insulator 10 patterned
on an anode 12. The anode has two functions. FIG. 1A also depicts a
substrate 6 separated from mask 8. One is as a supporting material
for the patterned insulator 10 to maintain its integrity and
alignment since the pattern may be topologically complex (e.g.,
involving isolated "islands" of insulator material). The other
function is as an anode for the electroplating operation. CC mask
plating selectively deposits material 22 onto a substrate 6 by
simply pressing the insulator against the substrate then
electrodepositing material through apertures 26a and 26b in the
insulator as shown in FIG. 1B. After deposition, the CC mask is
separated, preferably non-destructively, from the substrate 6 as
shown in FIG. 1C. The CC mask plating process is distinct from a
"through-mask" plating process in that in a through-mask plating
process the separation of the masking material from the substrate
would occur destructively. As with through-mask plating, CC mask
plating deposits material selectively and simultaneously over the
entire layer. The plated region may consist of one or more isolated
plating regions where these isolated plating regions may belong to
a single structure that is being formed or may belong to multiple
structures that are being formed simultaneously. In CC mask plating
as individual masks are not intentionally destroyed in the removal
process, they may be usable in multiple plating operations.
Another example of a CC mask and CC mask plating is shown in FIGS.
1D-1F. FIG. 1D shows an anode 12' separated from a mask 8' that
comprises a patterned conformable material 10' and a support
structure 20. FIG. 1D also depicts substrate 6 separated from the
mask 8'. FIG. 1E illustrates the mask 8' being brought into contact
with the substrate 6. FIG. 1F illustrates the deposit 22' that
results from conducting a current from the anode 12' to the
substrate 6. FIG. 1G illustrates the deposit 22' on substrate 6
after separation from mask 8'. In this example, an appropriate
electrolyte is located between the substrate 6 and the anode 12'
and a current of ions coming from one or both of the solution and
the anode are conducted through the opening in the mask to the
substrate where material is deposited. This type of mask may be
referred to as an anodeless INSTANT MASK.TM. (AIM) or as an
anodeless conformable contact (ACC) mask.
Unlike through-mask plating, CC mask plating allows CC masks to be
formed completely separate from the fabrication of the substrate on
which plating is to occur (e.g. separate from a three-dimensional
(3D) structure that is being formed). CC masks may be formed in a
variety of ways, for example, a photolithographic process may be
used. All masks can be generated simultaneously, prior to structure
fabrication rather than during it. This separation makes possible a
simple, low-cost, automated, self-contained, and internally-clean
"desktop factory" that can be installed almost anywhere to
fabricate 3D structures, leaving any required clean room processes,
such as photolithography to be performed by service bureaus or the
like.
An example of the electrochemical fabrication process discussed
above is illustrated in FIGS. 2A-2F. These figures show that the
process involves deposition of a first material 2 which is a
sacrificial material and a second material 4 which is a structural
material. The CC mask 8, in this example, includes a patterned
conformable material (e.g. an elastomeric dielectric material) 10
and a support 12 which is made from deposition material 2. The
conformal portion of the CC mask is pressed against substrate 6
with a plating solution 14 located within the openings 16 in the
conformable material 10. An electric current, from power supply 18,
is then passed through the plating solution 14 via (a) support 12
which doubles as an anode and (b) substrate 6 which doubles as a
cathode. FIG. 2A, illustrates that the passing of current causes
material 2 within the plating solution and material 2 from the
anode 12 to be selectively transferred to and plated on the cathode
6. After electroplating the first deposition material 2 onto the
substrate 6 using CC mask 8, the CC mask 8 is removed as shown in
FIG. 2B. FIG. 2C depicts the second deposition material 4 as having
been blanket-deposited (i.e. non-selectively deposited) over the
previously deposited first deposition material 2 as well as over
the other portions of the substrate 6. The blanket deposition
occurs by electroplating from an anode (not shown), composed of the
second material, through an appropriate plating solution (not
shown), and to the cathode/substrate 6. The entire two-material
layer is then planarized to achieve precise thickness and flatness
as shown in FIG. 2D. After repetition of this process for all
layers, the multi-layer structure 20 formed of the second material
4 (i.e., structural material) is embedded in first material 2 (i.e.
sacrificial material) as shown in FIG. 2E. The embedded structure
is etched to yield the desired device, i.e. structure 20, as shown
in FIG. 2F.
Various components of an exemplary manual electrochemical
fabrication system 32 are shown in FIGS. 3A-3C. The system 32
consists of several subsystems 34, 36, 38, and 40. The substrate
holding subsystem 34 is depicted in the upper portions of each of
FIGS. 3A to 3C and includes several components: (1) a carrier 48,
(2) a metal substrate 6 onto which the layers are deposited, and
(3) a linear slide 42 capable of moving the substrate 6 up and down
relative to the carrier 48 in response to drive force from actuator
44. Subsystem 34 also includes an indicator 46 for measuring
differences in vertical position of the substrate which may be used
in setting or determining layer thicknesses and/or deposition
thicknesses. The subsystem 34 further includes feet 68 for carrier
48 which can be precisely mounted on subsystem 36.
The CC mask subsystem 36 shown in the lower portion of FIG. 3A
includes several components: (1) a CC mask 8 that is actually made
up of a number of CC masks (i.e. submasks) that share a common
support/anode 12, (2) precision X-stage 54, (3) precision Y-stage
56, (4) frame 72 on which the feet 68 of subsystem 34 can mount,
and (5) a tank 58 for containing the electrolyte 16. Subsystems 34
and 36 also include appropriate electrical connections (not shown)
for connecting to an appropriate power source for driving the CC
masking process.
The blanket deposition subsystem 38 is shown in the lower portion
of FIG. 3B and includes several components: (1) an anode 62, (2) an
electrolyte tank 64 for holding plating solution 66, and (3) frame
74 on which the feet 68 of subsystem 34 may sit. Subsystem 38 also
includes appropriate electrical connections (not shown) for
connecting the anode to an appropriate power supply for driving the
blanket deposition process.
The planarization subsystem 40 is shown in the lower portion of
FIG. 3C and includes a lapping plate 52 and associated motion and
control systems (not shown) for planarizing the depositions.
Electrochemical Fabrication provides the ability to form prototypes
and commercial quantities of miniature objects, parts, structures,
devices, and the like at reasonable costs and in reasonable times.
In fact, Electrochemical Fabrication is an enabler for the
formation of many structures that were hitherto impossible to
produce. Electrochemical Fabrication opens the spectrum for new
designs and products in many industrial fields. Even though
Electrochemical Fabrication offers this new capability and it is
understood that Electrochemical Fabrication techniques can be
combined with designs and structures known within various fields to
produce new structures, certain uses for Electrochemical
Fabrication provide designs, structures, capabilities and/or
features not known or obvious in view of the state of the art.
A need exists in various fields for miniature devices having
improved characteristics, reduced fabrication times, reduced
fabrication costs, simplified fabrication processes, and/or more
independence between geometric configuration and the selected
fabrication process.
A need exists in the field of miniature device fabrication for
improved fabrication methods and apparatus.
SUMMARY OF THE INVENTION
An object of various aspects of the invention is to provide devices
(e.g. structures, objects, parts, components, and the like) having
improved characteristics.
An object of various aspects of the invention is to provide reduced
fabrication time for producing devices (e.g. prototype
devices).
An object of various aspects of the invention is to provide reduced
fabrication costs for producing devices (e.g. prototype
devices)
An object of various aspects of the invention is to provide
simplified fabrication processes for producing devices.
An object of various aspects of the invention is to provide more
independence between geometric configuration of a device and the
selected fabrication process.
A need exists in the field of miniature device fabrication for
improved fabrication methods and/or apparatus.
Other objects and advantages of various aspects of the invention
will be apparent to those of skill in the art upon review of the
teachings herein. The various aspects of the invention, set forth
explicitly herein or otherwise ascertained from the teachings
herein, may address any one of the above objects alone or in
combination, or alternatively may address some other object of the
invention ascertained from the teachings herein. It is not intended
that any specific aspect of the invention (that is explicitly set
forth below or that is ascertained from the teachings herein)
address any of the objects set forth above let alone address all of
these objects simultaneously, while some aspects may address one or
more of these objects or even all of these objects
simultaneously.
In a first aspect of the invention a sensor includes at least two
sets of capacitor plates wherein each set of plates includes a
plurality of plates.
In a second aspect of the invention, an actuator includes at least
two sets of capacitor plates wherein each set includes a plurality
of plates and wherein a motion of the actuator is perpendicular to
a plane of the plates.
In a third aspect of the invention, an actuator includes at least
two sets of capacitor plates wherein each set includes a plurality
of plates and wherein a motion of the actuator is in a direction
parallel to a plane of the plates, and wherein a portion of the
plurality of plates in one set are positioned in a first plane
while another portion of the plurality of the plates of the one set
are positioned in a second plane offset from the first plane.
In a fourth aspect of the invention, an actuator includes at least
two sets of capacitor plates wherein each set includes a plurality
of plates and wherein a motion of the actuator is in a direction
parallel to a plane of the plates, and wherein the plurality of
plates in one set are positioned in an array that extends in three
dimensions.
In a variation of the first through fourth aspects of the
invention, the sensor or actuator is formed at least in part via
electrochemical fabrication.
In a fifth aspect of the invention an LVDT sensor is formed at
least in part via electrochemical fabrication.
In a sixth aspect of the invention an actuator is formed at least
in part via electrochemical fabrication.
In a seventh aspect of the invention a sensor is formed at least in
part via electrochemical fabrication.
In an eighth aspect of the invention an electrostatic actuator
includes at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode and/or the moveable member is configured to have a
contour that leads to a spacing between moveable member and the
electrode when the moveable member is in its deflected position
toward the electrode which is more uniform than when the moveable
member is in an undeflected position.
In a ninth aspect of the invention an electrostatic actuator
includes at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode and/or the moveable member has a configuration that
brings portions of the electrode and member closer together without
significantly interfering with the movement of the member.
In a tenth aspect of the invention an electrostatic actuator
includes at least one moveable member and at least one actuation
electrode for causing movement of the moveable member wherein the
electrode has at least one sidewall or at least one protrusion in a
region that reduces the separation between the electrode and the
member without hindering the motion of the member.
In an eleventh aspect of the invention an electrostatic actuator
includes at least one moveable member and at least two actuation
electrodes that can be activated to create forces that pull the
moveable member in opposing directions.
In a twelfth aspect of the invention an electrostatically actuated
micro-mirror scanning system includes contoured electrodes that
allow a reduced drive voltage without hindering mirror
movement.
In a thirteenth aspect of the invention a structure includes a
multi-level micro flow channel.
In a fourteenth aspect of the invention a metal mold includes a
plurality of levels having features with dimensions on the order of
10s of microns or less.
In a fifteenth aspect of the invention a process for forming a
multilayer microdevice, comprising: (a) forming a layer of at least
one material on a substrate that may include one or more previously
deposited layers of one or more materials; (b) repeating the
forming operation of "(a)" one or more times to form at least one
subsequent layer on at least one previously formed layer to build
up a three-dimensional structure from a plurality layers; wherein
the forming of at least one layer, comprises: (1) supplying a
substrate on which one or more successive depositions of one or
more materials may have occurred; (2) supplying a mask having a
desired pattern or capable of being activated to effectively
deposit or etch a desired pattern of material; (3) bringing the
mask and the substrate into contact or proximity such that
electrochemical process pockets are formed having a desired
registration with respect to any previous depositions and providing
a desired electrolyte solution such that the solution is provided
within the electrochemical process pockets; and (4) applying a
desired electrical activation to cause a desired material to be
deposited onto the substrate or removed from the substrate in
preparation for deposition of a material onto the substrate;
wherein the microdevice includes one or more of the following: an
accelerometer, a switch, a valve, a 3-D tilt mirror, a fluid well,
a tool for producing other microstructures or structures with
micro-patterning, an actuator including a contoured electrode, a
bellows controlled valve, an actuator with pull down and pull up
electrodes, a valve comprising a shape memory device, a bistable
valve, a device at least partly surrounded by a conductive shield
wall.
In a sixteenth aspect of the invention a microdevice, includes: a
plurality of layers of successively deposited material, wherein the
deposition of each layer of material comprises, (a) deposition of
at least a first material; and (b) deposition of at least a second
material; and wherein at least a portion of the first or second
material is removed after deposition of the plurality of layers;
and wherein a structure resulting from the deposition and the
removal provides at least one structure that can function as (1) an
accelerometer, (2) a toroidal inductor, (3) a switch, (4) a valve,
(5) a helical inductor, (6) a 3-D tilt mirror, (7) a fluid well,
(8) an antenna, or (9) a mold.
In a seventeenth aspect of the invention a method of manufacturing
a microdevice includes: depositing a plurality of adhered layers of
material, wherein the deposition of each layer of material
comprises, a. selective deposition of at least a first material; b
deposition of at least a second material; and c. planarization of
at least a portion of the deposited material; removing of at least
a portion of the first or second material after deposition of the
plurality of layers; wherein a structure resulting from the
deposition and the removal provides at least one structure that can
function as (1) an accelerometer, (2) a toroidal inductor, (3) a
switch, (4) a valve, (5) a helical inductor, (6) a 3-D tilt mirror,
(7) a fluid well, (8) an antenna, or (9) a mold.
In a eighteenth aspect of the invention a microaccelerometer
includes: a proof mass; and at least one of a plurality of
spring-like structures for supporting the proof mass relative to a
substrate; where a portion of the plurality of spring-like
structures attach to the proof mass below a center of mass of the
proof mass and a plurality of the spring-like structures attach to
the proof mass above the center of mass of the proof mass; or a
plurality of spring-like structures for supporting the proof mass
relative to a substrate; where a portion of the plurality of
spring-like structures attach to the proof mass in a common plane
that includes the center of mass of mass of the proof mass.
In a nineteenth aspect of the invention a microvalve that includes
a valve seal and wherein at least one of the valve seat or valve
seal is supported by at least one corrugated support structure.
In a twentieth aspect of the invention a 3-D tilt mirror including
features with dimensions on the order of 10s of microns comprising
a rotatable mirror structure with a reflective surface that is
supported by at least one spring-like structure, wherein the
spring-like structure is formed from the same material as that
which forms the reflective surface.
Further aspects of the invention will be understood by those of
skill in the art upon reviewing the teachings herein. Other aspects
of the invention may involve combinations of the above noted
aspects of the invention. Other aspects of the invention may
involve apparatus that can be used in implementing one or more of
the above method aspects of the invention. These other aspects of
the invention may provide various combinations of the aspects
presented above as well as provide other configurations,
structures, functional relationships, and processes that have not
been specifically set forth above.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1C schematically depict a side view of various stages of a
CC mask plating process, while FIGS. 1D-G depict a side view of
various stages of a CC mask plating process using a different type
of CC mask.
FIGS. 2A-2F schematically depict side views of various stages of an
electrochemical fabrication process as applied to the formation of
a particular structure where a sacrificial material is selectively
deposited while a structural material is blanket deposited.
FIGS. 3A-3C schematically depict side views of various example
subassemblies that may be used in manually implementing the
electrochemical fabrication method depicted in FIGS. 2A-2F.
FIG. 4 illustrates a pressure sensor utilizing a plurality of
stacked capacitor plates according to a first embodiment.
FIG. 5 illustrates an actuator utilizing a plurality of stacked
capacitor plates according to a second embodiment.
FIG. 6A illustrates a moveable portion of an actuator according to
a third embodiment where the moveable portion includes a plurality
of stacks and each stack includes a plurality of individual
capacitor plates.
FIG. 6B illustrates an expanded view of a portion of FIG. 6A.
FIG. 6C illustrates a top view of the top level of partially
overlapping fixed and moveable capacitor plates for the actuator of
FIGS. 6A and 6B.
FIG. 7 illustrates a schematic representation of a linear variable
differential transformer (LVDT).
FIGS. 8A-8D depict various views of a switch according to an
embodiment of the invention.
FIG. 9A illustrates the mechanical portion of an accelerometer
which includes a proof mass supported by eight arms.
FIG. 9B illustrates a three-dimensional version of an accelerometer
that can be fabricated using electrochemical fabrication.
FIG. 10 illustrates another embodiment of the present invention
where a check valve is provided.
FIG. 11 depicts a pressure controlled bellows valve that can be
made using electrochemical fabrication.
FIGS. 12A-12F depicts various stages in a process for forming a
valve according to an embodiment of the invention.
FIGS. 13A and 13B depict a valve which is bistable in
operation.
FIG. 14 depicts a perspective view of a three-dimensional tilt
mirror.
FIG. 15 illustrates an SEM image of a fabricated mirror of the
design of FIG. 14.
FIGS. 16A-16C depicts various views of a mirror according to an
embodiment of the invention.
FIGS. 17A-17C depict various views of a mirror according to an
embodiment of the invention.
FIGS. 18A-18C depict various views of a mirror according to an
embodiment of the invention.
FIGS. 19A-19C depicts various mirror configurations according to
various embodiments of the invention.
FIGS. 20A-20B depict perspective views of a mirror design and a
fabricated mirror, respectively, according to an embodiment of the
invention.
FIGS. 21A-21B depict a scanning mirror and an actuation electrode,
respectively, for an embodiment of the invention.
FIG. 21C depicts another alternative embodiment where electrode
elevation is contoured to approximate, at least in part, the path
of traveled by the mirror.
FIG. 22 depicts a structure containing a number of microchannels
connecting wells.
FIG. 23 shows a cross section of a coaxial extrusion die designed
to be fabricated with electrochemical fabrication technology and
which is capable of extruding up to three different materials.
FIGS. 24A-24C depict samples of extrudates as might be generated
from the extrusion die like that of FIG. 23.
FIG. 25 shows how a single vacuum manifold can connect all the
vacuum holes in a surface according to an embodiment of the
invention.
FIGS. 26A and 26B illustrate different probe tip
configurations.
FIG. 27 illustrates a pressure sensor whose movement is controlled
by a bellows-like structure.
FIGS. 28A-28D depicts various actuators according to an embodiment
of the invention.
FIGS. 29A and 29B depict perspective view of the actuators similar
to those in FIGS. 28A and 28B.
FIGS. 30A-30F depict various switches according to different
embodiments of the invention.
FIGS. 31A-31C depicts various electrode and beam relationships
according to different embodiments of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of
Electrochemical Fabrication that are known. Other electrochemical
fabrication techniques are set forth in the '630 patent referenced
above, in the various previously incorporated publications, in
patent applications incorporated herein by reference, still others
may be derived from combinations of various approaches described in
these publications, patents, and applications, or are otherwise
known or ascertainable by those of skill in the art. All of these
techniques may be combined with those of the present invention to
yield enhanced embodiments.
Some embodiments present miniature sensors or actuators that may be
formed totally or in part using Electrochemical Fabrication
techniques. Some of these devices may be formed monolithically in
an Electrochemical Fabrication process. Some of these devices make
use of applied electric fields to cause motion. Some embodiments
use parallel plate gap closing effects while others use comb drive
type effects. Some devices make use of applied electric fields to
detect motion. A change in distance between capacitor plates
produces a change in capacitance which can be electrically
measured). Devices that rely on electric field properties to cause
or sense motion are sometimes termed "electrostatic devices" even
though the electric fields supplied or detected may not be static.
Electrostatic devices offer several advantages: (1) their use is
simple as it is relatively easy to apply and measure voltages, (2)
relatively simple geometries may be usable, (3) at the distance
scales involved in miniature devices (e.g. meso-scale and
microscale devices) electrostatic forces become significant enough
to move and manipulate mechanisms, (4) electrostatic devices may be
configured for low power consumption, (5) electrostatic devices can
operate quickly, and (6) Electrostatic devices can be shielded from
the influence of external fields while producing little
electromagnetic interference themselves. The designation of devices
as "electrostatic" does not imply that the electric field doesn't
change or that only DC currents are involved, but rather that the
physics of electric fields dominates over the physics of any
induced magnetic fields. In fact, electrostatic devices have been
operated over a large frequency range (e.g. up to several kilohertz
or more).
Electrostatic devices proposed or developed have typically suffered
from some problems: (1) though electrostatic forces achieved have
been sufficient for some applications, they have been inadequate
for others; (2) high actuation voltages have typically been
necessary, e.g. in excess of 100 volts, and/or (3) some devices
have exhibited unpredictable behavior or stiction which may be the
result of production of unintended electric fields. Some
embodiments of electrostatic actuators and sensors to be discussed
hereafter lessen the severity of some of these problems: (1) by
producing higher forces at lower actuation voltages, and/or (2) by
providing higher capacitance changes at a given displacement for
capacitance sensing, (3) by providing higher conductivity material,
as compared to silicon, which may help reduce unintended charging,
reduce power consumption, and allow operation at higher
frequencies.
EFAB enables numerous new electrostatic actuator embodiments that
create greater electrostatic force. As greater electrostatic force
typically translates into greater capacitance structures of these
embodiments can be advantageously used in sensor applications as
well.
Linear electrostatic actuators, such as comb drives, typically
employ some form of parallel plate configuration, in which the gap
spacing between plates is fixed, while the area of overlap between
plates changes during actuation, typically resulting in a linear
motion and a linear relationship between applied voltage and
displacement. The main issues associated with linear electrostatic
actuators actuation force vs. voltage and total displacement or
throw. By far the most widely used linear electrostatic actuator is
the comb drive actuator, in which a series of interdigitated finger
shaped electrodes provide an attractive force. Comb drive actuators
previously proposed or developed provided a 2D array of comb
fingers. The actuation force may be maximized by increasing the
number of fingers, reducing the gap between the fingers, and
increasing the thickness or depth of the fingers. Comb drives
produced by surface micromachining have gaps of typically 1 or 2
microns and thickness of 2 microns in large arrays of dozens or
even hundreds of comb fingers. In order to further increase the
force, high-aspect ratio processes have been used to create very
deep comb fingers. For example, DRIE-based comb fingers greater
than 100 microns in thickness have been created. Limitations of
conventional high-aspect ratio processing generally have required
an increased comb gap at greater etch depths which have somewhat
reduced the advantages of using high aspect ratio structures. These
high aspect ratio comb drive actuators are essentially tall,
extruded 2D comb drive arrays.
According to certain embodiments of the present invention, 3D
arrays of comb drives containing many more combs than possible in a
2D array may be fabricated. Furthermore, according to some of these
embodiments, it is possible to produces such actuators without a
gap width to structure thickness dependence as thickness may be
increased by simply adding more layers. In these some of these
embodiments (to be discussed further hereafter), more combs are
created in a smaller cross-sectional area thus allowing greater
forces to be generated at lower voltages. Alternatively, or
additionally, supporting spring and framework can be designed to
allow greater displacement and greater stability at higher
operating voltages. In still other embodiments such actuators may
be combined with dielectric stops and the like to inhibit shorting.
In still further embodiments it is possible to configure actuators
to provide rotary motions as opposed to linear motion. In still
further embodiments comb drives may be configured to provided
multi-directional motion.
Electrostatic actuators may also be designed using parallel plates
that create a driving force that attracts selected plates to one
another thereby causing a motion that changes a gap between
adjacent plates as they move. Conversely, sensors may be formed
that take advantage of the change in capacitance that results from
separation of the plates changing (pressure sensors and
accelerometers). These actuators typically produce higher forces
than to comb drives but are nonlinear in their operation.
Typically, these actuators are implemented by placing an electrode
underneath a structure, the electrode then pulls the structure
downwards. Most tilting mirror devices use some version of this
principal.
Some embodiments of the present benefit from a greater flexibility
in arrangement of the gap closing electrodes that may be achieved
via three-dimensional structuring of the actuator that is allowed
by a true multi-layer fabrication process (e.g. by the ability to
use more than 5 to 10 layers). For example, in some embodiments
electrodes may be placed above and below a device for bidirectional
actuation. In other embodiments a stationary actuator can act in
the middle of two moving members. In still other embodiments
enhanced sensor may be provided such as 2-axis and 3-axis
accelerometers. In still other embodiments, stacking of electrode
plates may be used to obtain a greater measure of change for a
given displacement as opposed to implementations where single pair
of plates are used in detecting a displacement.
With gap closing actuators, the force is generally approximately
proportional to the square of the gap distance. This can be a
problem when a large range of motion is required. In the
state-of-the-art, the electrodes are placed at a distance from the
moving member, so that the moving member does not touch the
electrode throughout its full range of motion. Unfortunately, this
often requires the electrode to be placed at a substantial distance
from the moving member, which drastically reduces the available
force. It then becomes difficult to initiate motion in the moving
member. As a result, tilt mirror devices for example typically
require large operating voltages due to the large distance between
the mirror and electrode. Furthermore, this conventional approach
results in a very nonlinear actuator behavior, requiring use of
complex control schemes to compensate for the increase in force as
the gap closes. In fact as it is typical for the spring force to
increase only linearly with displacement, a maximum point in
displacement can occur where the attractive force exceeds the
return force and snapping closure occurs.
In some embodiments of the present invention, electrode and or
moving member configuration is modified so that the actuating
electrode is close to the moving member but does not intersect the
path of motion. In some embodiments the electrode is supplied with
a stairstep configuration (e.g. the electrode is formed from a
stack of layers whose structure approximates a curve under which a
cantilever beam will bend. It is believed that such a configuration
may provide a substantial increase in force (or allow a significant
reduction in driving voltage) while maintaining a desired extent of
motion. Alternatively, the stiffness of the return springs could be
increased without an increase in drive voltage to change the
mechanical resonance frequency of the member. In other embodiments
the actuation electrode for a cantilever beam may not be positioned
so that it is only located, for example, in a plane below the beam
but instead it may be configured to be both below and to the sides
(or at least approaching the sides) of the beam such that the
distance between the beam and portions of electrode is dramatically
decreased while still allowing full motion of the beam. In still
other embodiments, the beam may be made to move in more than one
direction using multiple electrodes. In other embodiments, the
electrodes may be both underneath a moving member and located to an
elevated position beyond the end of the moving member. For example,
the electrodes that control the multi-directional movement of a
scanning mirror may be located below their respective portions of
the scanning mirror as well as at an elevated position beyond the
lateral extents of the moving mirror surface. In still further
embodiments, the electrodes may be partially contoured to bring its
surface closer to a moving member in such away as not to hinder the
required motion while the moving member itself includes surface
level modifications (e.g. deviates from a planar configuration) to
bring portions of its surface closer to that of the electrode. In
still further embodiments, the electrode may contain no surface
level modifications (e.g. it may remain planar) while the moving
member contains surface level modifications.
In still further embodiments, closing gap actuators may be stacked
in series to increase the total throw of the actuator. An example
is shown on pages 56 and 57. A 3D volume of such electrodes could
be used to construct an actuator `fabric` with high displacement
and force.
Multiple electrostatic actuators can be configured to achieve
complex functionality, such as for use as multi-axis component
alignment structures. In some embodiments, required electrical
traces may be formed in an EFAB process on a dielectric along with
the formation of the rest of the devices or structures. In other
embodiments it is also possible with EFAB to embed the conductive
lines inside an insulating matrix as part of the composition of the
supporting structural member. This allows multiple signals to be
routed within a mechanical structure with minimal impact on the
design and performance of the structure.
Electrostatic micromotors may also be made practical according to
some embodiments of the invention by allowing formation of motors
with both top drive and bottom drive electrodes as opposed to the
top drive or side drive electrodes previously proposed.
FIG. 4 illustrates a pressure sensor according to a first
embodiment. This pressure sensor includes a plurality of stacked
capacitor plates that may by used to enhance the sensitivity of any
displacement caused by a pressure differential. The pressure sensor
of the present embodiment includes a base plate 102 through which
conductive leads 104 and 106 extend. Conductive lead 106 connects
to walls 108 and flexible lid member 112 when a pressure P is
exerted on the outside lid member 112 which exceeds a pressure P
inside a chamber 114 formed by base 102 walls 108 and lid 112, a
downward deflection of lid 112 occurs which causes a deflection of
capacitive plates 116(a), 116(b) and 116(c) relative to capacitive
plates 118(a), 118(b), and 118(c). This deflection causes a change
in the capacitance of the capacitor that is formed by set of plates
116(a)-116(c) and 118(a)-118(c). This change in capacitance can be
detected and correlated to a pressure differential. Due to the
existence of multiple capacitor plates, the sensitivity of the
sensor may be increased over that of a single set of or level of
plates.
In alternative embodiments more then three pairs of capacitor
plates may be used. In some embodiments a single pair of capacitor
plates may suffice while in other embodiments many pairs of
capacitor plates might be appropriate. In some embodiments the
hermetic sealing techniques set forth in U.S. patent application
Ser. No. 60/379,182 and in U.S. patent application Ser. No.
60/430,809 filed Dec. 4, 2002 having MEMGen Corporation Docket No.
P-US021-B-MG may be used to form pressure sensors. In some
alternative embodiments conductive leads 106 and 104 may extend
from a wall of the sensor as opposed to through the base. In such
alternative embodiments, if the walls form part of the conductive
path that lead to a set of the capacitor plates, then the
conductive lead for the other set of plates may be separated from
the wall by a dielectric material where the dielectric material may
be added to the structure after its formation or may be added to
the structure during its formation such as during formation on a
layer-by-layer basis by electrochemical fabrication. In still other
embodiments the walls and the exposed surface of lid 112 may be of
the dielectric material or a dielectric coated conductor. In still
other embodiments fixed capacitor plates 118(a)-118(c) may be
connected to a portion of the walls as opposed to being mounted on
the base. In some embodiments the sensors may detect, for example,
pressure, displacement, or function as enhanced-sensitivity
accelerometers (assuming the lid 112 doesn't effective displacement
significantly and that moveable plates 116(a)-116(c) have
sufficient mass).
A second embodiment is depicted in FIG. 5. As in the first
embodiment, FIG. 5 depicts a side view relative to a plurality of
layers from which the structure was formed. FIG. 5 depicts an
actuator as opposed to the sensor of FIG. 4. The actuator consists
of a shaft 122 that is connected to spring-like return arms 124 and
126 where the return arms are mounted in a fixed position at
location 128 and 132. Connected to shaft 122 are capacitor plates
136(a)-136(c). A second set of capacitor plates 138(a)-138(c) are
mounted to a frame (not shown) which may be the same frame to which
portions 128 and 132 of return arms are directly or indirectly
mounted. As a voltage V is applied between the two sets of
capacitor plates, shaft 122 is displaced. Since the total force
associated with the displacement of shaft 122 is related to the
capacitance and since the capacitance is related to the effective
area of the plates, by using multiple sets of plates a higher
driving force can be obtained for a given cross-sectional area of
individual plates. In some embodiments the actuator of FIG. 5 may
be included in a housing in much the same manner as illustrated in
FIG. 4, with the possible exception of an opening in a base or a
lid such that the shaft may be coupled to an external element that
is to be actuated. In alternative embodiments coupling between the
shaft and an external component may occur via a non-physical link
such as, for example, via capacitive, inductive, or magnetic
coupling. In some embodiments a single pair of capacitive plates
might suffice while in other embodiments many more sets of
capacitor plates might be used. In still other embodiments sets of
capacitive plates might be connected to different shafts and each
of the shafts linked to a primary shaft such that the total force
is increased still further. In some embodiments hundreds or even
thousands of sets of plates may be used.
In the first and second embodiments the side views illustrated do
not depict cross-sectional dimensions of the plates (along the
dimension extending into the page). The plates may take on
rectangular dimensions or circular dimensions or any other
configuration that is appropriate to the constraints of a given
application. The embodiment of FIG. 5 may be used to control, for
example, a shutter mechanism in an optical application or a worm
drive in an application where extended motion is required.
In some embodiments, the capacitor plates need not be planar and
when used herein unless otherwise indicated indications of
"parallel to", or "perpendicular to" capacitor plates should be
interpreted as relative to a plane of a relevant portion of the
surface of a plate or plates.
A third embodiment of the invention is depicted in FIGS. 6A-6C.
FIG. 6A depicts a perspective view of the moving portion of an
actuator while FIG. 6B depicts an expanded view of a portion of the
structure of FIG. 6A such that individual capacitor plates can be
seen in several of the stacks. FIG. 6C depicts a top view of both
the moving elements and the fixed elements of the actuator of FIGS.
6A and 6B. The moving elements of actuator 6(a) include a plurality
of stacks 142a-142r of capacitor plates where each stack itself
includes a plurality of capacitor plates as illustrated in FIG. 6B
as 142a(1), 142a(2), 142a(3), etc. The moving elements also include
a shaft 144 and columns 146 that connect all of the capacitor
plates into a single structure. Shaft 144 is supported by
spring-like elements 148 and 150 which in turn have one end 152 and
154 connected to columns 156 and 158 that extend to a frame (not
shown). For clarity of presentation FIGS. 6A and 6B do not depict
the plurality of fixed capacitor plates that are interleaved
partially between the moving capacitor plates 142a(1)-142a(3), etc
and that would be supported by an appropriate structure relative to
the support columns 156 and 158. The upper layer of movable
capacitor plates 142a(1)-142r(1) are shown in FIG. 6C along with
spring-like return arms 148 and 150 and shaft 144. FIG. 6C also
depicts the upper level of fixed capacitor plates 162a(1)-162r(1).
Fixed capacitor plates 162a(1)-162r(1) are connected to a frame
(not shown) via connecting element 164. As a voltage is applied
between the moving plates and the fixed plates, the plates are
drawn into a tighter overlapping position thereby making shaft 144
move in direction 166. As with the embodiments of FIG. 4 and 5 the
embodiments of FIG. 6 can take on numerous alternative
configurations. For example the actuator of FIGS. 6A-6C may by
enclosed in a housing. In some embodiments, the return elements may
take forms different from those shown. In other embodiments, for
example, the number of stacks of capacitor plates may be reduced to
one or extended to many times the number depicted and likewise the
number of capacitor plates on any given stack may be decreased to
one or increased well beyond the number illustrated. In still other
embodiments instead of driving the structure of FIGS. 6A-6C by
applying a voltage of the desired magnitude, the structure may be
used as a sensor whereas a displacement of shaft 144 may give rise
to a change in capacitance which can in turn give rise to a
detectable electrical signal which can be correlated to the
displaced amount.
A fourth embodiment of the present invention provides a linear
variable differential transformer or LVDT which may be
monolithically produced by electrochemical fabrication. As
indicated in FIG. 7, the LVDT may consist of a primary transformer
coil 180 and two secondary transformer coils 182a and 182b.
Additionally, an armature of magnetically permeable material is
included that may move back and forth such that different amounts
of the armature may be located in secondary coils 182a or 182b.
Armature 184 may have a non-magnetically permeable extension
extending out of one or both ends of the secondary coils as
indicated by reference numbers 186a and 186b. In use, the LVDT may
be supplied with a voltage V1 on primary coils 180 and a voltage
difference V2 between the two secondary coils may be detected, to
yield a value which can be related to the position of armature 184.
Armature 184 is connected via elements 186a or 186b to a structure
whose position is to be measured. The detected voltage V2 may be
used to determine the position of the desired structure. Using
electrochemical fabrication windings of coils 180, 182a and 182b
may be formed out of a first material such as copper while armature
184 may be formed out of a material such a permalloy. Elements 186a
and 186b may be formed out of a suitable conductive or dielectric
materials. An insulating material may be formed between the
conductive elements 180, 182a, and 182b. Each of these materials as
well as a sacrificial material (and any other needed materials) may
be deposited (e.g. via electrochemical fabrication) on a
layer-by-layer basis until a plurality of layers have been
deposited to complete formation of the structure. As with the other
embodiments numerous alternatives are possible. For example, the
openings through coils 180, 182a, and 182b may be circular or
rectangular in shape while armature 184 may take on a corresponding
shape or other shape. The sensor of FIG. 7 may also be formed in a
protective housing that may also be formed via electrochemical
fabrication.
In some embodiments of the present invention the structures and
devices formed may have features as small as a micron, or
potentially even smaller, or as large as 10s or even 100s of
microns or even larger.
In some alternative embodiments, the sensors and actuators may use
alternatively shaped electrodes and actuation plates as discussed
herein above and as illustrated in some embodiments to be discussed
herein after.
Another embodiment of the instant invention is depicted in FIGS.
8A-8D. This embodiment is directed to a single pole double through
SPDT switch 202 whose moveable contact arm 204 is connected to a
substrate via pedestal 206. A plurality of plates 208(a)-208(d) via
vertical extending are connected element to 212. The moving member
ends with contact element 214(a) and 214(b) located between two
poles 216(a) and 216(b). These poles are supported by arms 218(a)
and 218(b), respectively, which in turn are connected to a base by
pedestals 222(a) and 222(b) respectively. The embodiment includes
additional actuator plates. A first set of which includes plates
224(a)-224(d) that are used to pull moving member 204 upward and
thus are used to cause contact element 214(a) to close with contact
element 216(a). Another set of actuation plates 228(a)-228(d) are
used to pull moving member 204 downward and thus to cause contact
element 214(b) to close with pole 216(b). Plates 228(a)-228(d) are
supported by vertical element 234 while plates 244(a)-224(d) are
supported by vertical element 232. A switch of this type may be
used to switch a signal between 3 states: (1) The open state--no
contact between 214(b) and 216(b) and no contact between 214(a) and
216(a), (2) Closed state No. 1 where a signal is carried between
elements 206 and 222(b) via contact between 214(b) and 216(b), (3)
Closed state No. 2 where a signal is carried between elements 206
and 222(a) via contact between elements 214(a) and 216(a). While
FIG. 8A depicts a side view, FIG. 8B depicts a back view and FIGS.
8C and 8D depict perspective views.
In alternative embodiments many variations of the design are
possible. For example different numbers or sizes of plates may be
used, different element dimensions are possible, the contact
materials of elements 214(a), 214(b), 216(a) and 216(b) maybe
different from the material of moving member 204 and arms 218(a)
and 218(b). In still other embodiments, actuation voltages may be
isolated from signals via independent lines that are separated by
dielectrics. In still further embodiments contact elements 216(a)
and 216(b) need not be located at the ends of flexible arm elements
but instead may be rigidly mounted on pedestals or the like.
As illustrated in the FIGS. 8A-8D the elements of the switch are
elevated above the substrate to reduce capacitance. In alternative
embodiments, the switch elements may be mounted to a substrate.
Multiple switch configurations are possible, including multipole
and multi throw switches. Multiple switches may be configured in
parallel for greater current handling and reliability, or in
series. The contact geometry can be modified. A wide range of
actuators may be used. Many different suitable electrostatic
actuator designs are possible. In other embodiments, actuation may
be implemented in other ways including magnetic, thermal,
pneumatic, bimetallic, acoustic, piezoelectric schemes. These
switches may operate at DC or RF frequencies. Switches which do not
require physical contact, such as those based on capacitive
coupling whether in series or shunt configuration for example, are
possible. Stops may be used to prevent shorting in the case of
capacitive switches, or spring brakes may be used to reduce the
impact force immediately prior to closure to improve reliability
and eliminate bounce.
Another embodiment of the invention is illustrated on FIG. 9A. FIG.
9A illustrates the mechanical portion of an accelerometer which
includes a proof mass 262 supported by eight arms, four of which
are labeled with reference numeral 264(a) and three of which are
labeled 264(b) while the eighth arm is invisible in this
perspective view. Each pair of arms in connected to a support
column 266 which in turn rests on a base not shown. Below the proof
mass a plate 268 is shown, the proof mass and the plate 268
function as a capacitor of variable capacitance. The capacitance
varies as accelerations in direction 272 cause relative
displacements of the proof mass and the plate 268. In the
illustrated design spring supports 264(a) and 264(b) are located
above and below the center of mass of proof mass 262. In
alternative embodiments a single set of spring supports may have
been located at the level of the center of the mass or at a
different level. In still other embodiments a different number of
spring supports are possible. In still other embodiments the
capacitance plate 268 may be suspended above a substrate so as to
reduce parasitic capacitance. And in still other embodiments
shorting between the plate 268 and proof mass 262 may be avoided
completely or at least minimized by including posts, tabs, stops or
other motion limiters that are made of dielectric materials and
located between the plate and the mask. Alternatively, motion
limiters may be made of conductive material that is mounted to the
substrate and that extends between the mass and the plate but does
not make electrical contact with the plate.
FIG. 9B illustrates a three dimensional version of an accelerometer
that can be fabricated using electrochemical fabrication. In this
embodiment, posts 282 and capacitor plates 284(a) and (b) and
286(a) and (b) as well as a plate located above proof mass 288 and
below proof mass 288 (plates not shown) are fixedly to a substrate.
Springs 292 allow the proof mass to move in the vertical direction
when an acceleration occurs in that direction. Such movement
changes the capacitance between the proof mass and the plates thus
allowing detection of the vertical acceleration. Springs 294 allow
the proof mass to move in the X direction (it is noted that springs
292 are inflexible in that direction). The movement of the proof
mass in the X direction can change the capacitance between
capacitor plates 286(a) and 286(b) and frame elements 296(a) and
296(b), respectively allowing the capacitance to change, thus
allowing detection of acceleration in the X direction. Similarly
acceleration in the Y direction can be detected by changing
capacitance between frame elements 302(a) and 302(b) and capacitor
plates 284(a) and 284(b), respectively. This movement is allowed by
springs 304. It should be noted that springs 292 and 294 are
substantially inflexible in the Y direction. The capacitance change
between elements 302(a) and 284(a) and 302(b) and 284(b) can be
detected thus allowing detection of acceleration in the Y
direction. In other embodiments other accelerometer configurations
are possible.
FIG. 10 illustrates another embodiment of the present invention
where a check valve is provided. The figure illustrates a
perspective view of one half of the check valve (the front half of
the check valve being removed so that the internal passages
extending through the valve can be seen). The valve includes valve
plate 312 located over an opening 314 which is at the end of
passages 316(a), 316(b) and 316(c). Valve plate 312 is supported by
a corrugated support bar or spring which allows the valve plate or
diaphragm to seal against the valve seat that surrounds opening
314. Openings 316(a)-316(c) allow three different fluids to enter
channel 318 and mix before exiting opening 314 when valve plate 312
is unseated due to pressure in chamber 318 exceeding the pressure
above plate 312. In FIG. 10 the valve plate is shown separated from
the seat surrounding opening 314 for illustrative purposes. In some
embodiments the valve may be normally closed so that it is opened
by an excess pressure in chamber 318. In other embodiments the
valve may be normally open where some elevated pressure above plate
312 is required to close the valve.
Though a check valve is illustrated in FIG. 10, a wide range of
microfluidic devices are possible, including various pumps and
valves. As an example of another fluid control device, FIG. 11,
depicts a pressure controlled bellows valve that can be made using
electrochemical fabrication. Application of positive and negative
relative hydraulic or pneumatic pressure to the bellows 332 via
channel 336 can cause the bellows 332 to seal against valve seat
334 to block fluid flow between chamber 338 and channel 342
A further example of a manufacturing process for a valve is
illustrated in FIGS. 12A-12F. The valve illustrated in these
figures is capable of proportional flow. In FIG. 12A, the valve has
been fabricated partway using an electrochemical fabrication
process of selective depositions, blanket depositions and
planarization operations. FIG. 12A depicts the block of material as
including a selective patterning of a sacrificial material 402 and
a structural material 404. The embedded valve is shown as having a
poppet 406, a valve seat 408, an inlet channel 412 and an outlet
channel 414. FIG. 12B depicts that a portion of the sacrificial
material 402 has been etched away using the top layer of structural
material 404 as a temporary masking layer. In FIG. 12C the
temporary masking layer has been planarized away and a layer of
shape memory alloy 416 (SMA, e.g., nickel-titanium) has been
deposited (e.g., by removing the substrate from the EFAB system and
placing in a sputtering chamber). In FIG. 1D, the structure has
been planarized, creating a layer that contains structural material
404, sacrificial material 402, and SMA 416. The pattern of the SMA
material is defined by the apertures that were in the temporary
masking layer and the resulting partial etch of sacrificial
material illustrated in FIG. 12B and was selected to form bendable
supports for the poppet 406 of structural material. It should be
noted that these supports only occupy a portion of the gap between
poppet and surrounding material (they do not form a continuous
membrane). One result of this is that the upper and lower volumes
of sacrificial material are interconnected to allow for etching of
the upper volume. FIG. 12E illustrate that additional
electrochemical fabrication steps have been performed to form a cap
of structural material. Finally, in FIG. 12F the sacrificial
material has been etched, forming fluid channels and cavities and
freeing the SMA supports to move the poppet against the valve seat.
The valve may be prepared for use by applying a force to the poppet
(e.g., by deforming the cap so as to provide a springy membrane
that pushes the poppet down) so as to preload the poppet against
the valve seat, causing the valve to close and the SMA material to
be deformed from its as-fabricated state. By heating the SMA
supports (e.g., by heating the valve overall, or passing current
through the SMA material), the SMA material will return to its
original state, opening the valve. Proportional action may be
obtained by controlling the amount of heating: a small amount of
heating will open the valve only slightly, while a large amount
will open it fully. It is noted that the inlet and outlet ports can
be reversed from what is shown. In other embodiments shape memory
alloys may be used in the formation cause biasing of various types
of components. In still other embodiments the halting of
electrochemical fabrication operations may be performed for the
purpose of performing other operations that etching and SMA
deposition.
In other embodiments, other valves of similar design can be
achieved by replacing the SMA supports in the valve described above
with other actuators including thermal actuators (e.g., thermal
bimorph, heatuator (a loop with segments having non-uniform
cross-sectional area), piezoelectric actuators, and so forth.
FIGS. 13A and 13B depict a valve which is bistable in operation:
this latching behavior minimizes current consumption. The valve
consists of a poppet 422 which is supported by a membrane 424 which
is in compression and is stable either when convex (bent upwards)
or concave (bent downwards). Corrugations in the membrane allow it
to contract slightly when transitioning from convex to concave.
Also attached to the poppet is a permanent magnet 426 which may be
fabricated as part of an electrochemical fabrication process. The
permanent magnet preferably forms the core of a solenoid with
multiple windings 428 (e.g. of copper). These windings may be
embedded in dielectric material 432 to provide mechanical
stabilization and electrical isolation. It should be noted that the
membrane also serves to guide the motion of the magnet. When
current is applied to the coil in one polarity, the magnet will be
drawn downwards as shown in FIG. 2B, pulling the poppet away from
the valve seat to open the valve, and also deforming the membrane
so that it is concave. At this time, current can be removed and the
valve will remain open. When it is desired to close the valve,
current of opposite polarity is applied to the coil, causing the
magnet to be repelled from the coil. This forces the membrane to
deform into its convex configuration, pushing the poppet against
the valve seat. In alternative embodiments the inlet 434 and outlet
ports 436 can be reversed from what is shown. Also, the diaphragm
need not be continuous so long as it is acceptable to immerse the
components below the diaphragm in the fluid controlled by the
valve, and so long as the additional fluid force acting to hold the
valve closed in the design shown can be overcome by the force
produced by the magnet and coil.
FIG. 14 depicts a perspective view of a three-dimensional tilt
mirror. The mirror assembly includes two support structures 452
which contact the substrate and four electrodes 454(a)-454(d) that
also rest upon a substrate. The mirror 456 is supported by springs
458(a) and 458(b), by ring 462, and by springs 464(a) and 464(b)
that allow rotation of the mirror and a direction substantially
perpendicular to that allowed by springs 458(a) and 458(b). To
cause tilting of the mirror a potential can be applied to one of
blocks 452 and one or more of electrodes 454(a)-454(d). In some
embodiments springs 458(a), 458(b), 464(a), and 464(b) maybe of the
same material as the mirror surface. In some embodiments the mirror
maybe thicker than the support springs. In still other embodiments
the mirror may have a ribbed structure, thereby strengthening it
while still maintaining a relatively low moment of inertia.
Similarly the outer ring 462 may be thicker than the support
springs. In still other embodiments, the drive electrodes may be
suspended above the substrate to reduce parasitic capacitance while
in other embodiments the springs of the mirror may be folded out of
the plane of the mirror to decrease the horizontal extents of the
monolithic mirror assembly. An SEM image of a fabricated mirror of
the design of FIG. 14 is illustrated in FIG. 15.
FIGS. 16A-16C illustrate an alternative embodiment of mirror
support springs. FIG. 16A depicts a top view showing a mirror 472
located above two support springs 472. FIG. 16B illustrates a
bottom view of the mirror 472 showing that support springs 474
contact a pedestal 476, which is located at the center of the
mirror. FIG. 16C shows a side view which indicates that springs 474
are spaced out of the plane of mirror 472. As a result of this
configuration less spring extent beyond the edge of mirror 472 is
needed to allow a particular spring constant to be obtained. As
such, an embodiment of this type can allow the horizontal extents
of a mirror assembly to be reduced and thus an array of mirrors to
be placed closer to one another.
FIGS. 17A-17C depict another alternative embodiment for reducing
the horizontal extents of the mirror assembly. As with FIGS.
16A-16C these figures only illustrate the springs and connections
associated with a single axis of motion. It is to be understood
that the other axis of motion may be obtained by appropriate design
extension. FIG. 17A depicts a top view of a mirror where the
springs and other rotational components are hidden beneath its
surface. FIG. 17B depicts a bottom view of the mirror, where an
outer ring attached to the bottom of the mirror can be seen with
spring elements for 482 shown connected to the ring 484 and to a
center piece 486. FIG. 17C indicates that springs 482 are separated
from mirror 488 by their contact with ring element 484. Spring
elements also connect to center post 486 which may be held in fixed
position and the mirror may be made to rotate about the axis of
springs 482.
Another alternative mirror embodiment is illustrated in FIGS.
18A-18C which depict side views of a mirror 494 spaced above
electrodes 496(a) and 496(b). At the center of mirror 494 a spring
element 498 is illustrated which allows pivoting in the directions
of electrodes 496(a) and 496(b). FIG. 18B illustrates the mirror
tilted towards electrode 496(b) while FIG. 18C depicts mirror
tilted toward electrode 496(a). Instead of using a planer electrode
as is typical, the electrodes of this embodiment have a contoured
shape which allows them to be positioned closer to the mirror
surface to decrease the voltage required to cause it to rotate
while also maintaining a position that does not hinder the movement
of the mirror.
FIGS. 19A-19C depict further alternative scanner mirror
embodiments. In FIG. 19A scanning mirror 502 is positioned above
electrodes 504(a) and 504(b) and a spring element 506 is located at
the center of mirror 502 this allows the mirror to rotate toward
either electrode 504(a) or 504(b). The distinguishing feature of
this embodiment as compared to the embodiment of FIGS. 18A-18C is
that only the outer extents of the mirror are positioned at an
elevated level while the portions of the electrodes approaching the
center of the mirror remain flat. In FIG. 19B, mirror 512 is
positioned above electrodes 514(a) and 514(b). Spring element 516
allows the mirror to pivot toward the electrodes which in this case
have an elevated configuration toward the center of the mirror
without any electrode elevation near the sides of the mirror.
Additionally in this embodiment stops of dielectric material 518
are located on electrodes 514(a) and 514(b) so as to inhibit mirror
512 from contacting the electrodes. FIG. 19C, is similar to 19B
with the exception that dielectric stops 528 are located on the
bottom of mirror 522 as opposed to on electrodes 524(a) and
524(b).
Another alternative embodiment is depicted in FIGS. 20A and 20B.
FIG. 20A depicts a perspective view of a mirror 542 positioned
above electrodes 544(a) and 544(b). The electrodes of this
embodiment have a similar configuration to those of FIGS. 18A-18C.
In the examples of FIGS. 18A-20A, the electrodes are shown as
having smoothed faced slanted surfaces. Such smoothness is
obtainable in some embodiments potentially by performing an
additional deposition operation after formation of all layers of a
structure and release of the structure from a sacrificial material.
However in other embodiments the electrodes may remain with slanted
surfaces with a stair step configuration as the height of the
electrodes would be formed from a series of layers stacked one upon
the other. FIG. 20B depicts an SEM image of a fabricated mirror of
the configuration shown in FIG. 20A. The stair step nature of the
electrodes can be seen in this figure.
Another alternative scanning mirror embodiment is illustrated in
FIGS. 21A-21C. FIG. 21A depicts a scanning mirror, very similar to
the scanning mirror of FIG. 14 with the difference that electrodes
554(a)-554(d) have an elevated configuration as opposed to the flat
configuration of FIG. 14. FIG. 21B depicts layer contour levels of
electrode 554(c), where the center portion 556 of electrode 554(c)
is at the lowest level while portion 558 is at an elevated level
with regions between 556 and 558 at intermediate levels. Similarly
562 is at an elevated level with portions between 556 and 562 at
intermediate levels. FIG. 21C depicts another alternative
embodiment where electrode elevation is contoured to approximate,
at least in part, the path of travel by the mirror. In FIG. 21C the
electrodes have a curved configuration while in FIG. 21A and 21B
had a square configuration.
Many additional alternative mirror embodiments are possible. In
some such alternatives densely packed fields of components that
include mirrors or other relatively high voltage components or
components that carry high frequency signals may benefit from the
fabrication of walls of conductive material around their perimeter.
These walls of conducted material may be grounded, thereby helping
to shield nearby components from negative influenced associated
with the electrical activity of other components. Similarly such
walls may help shield the other components from the electrical
activity of the surrounded components.
Another embodiment of the present invention is illustrated in
Fabricated device of FIG. 22. FIG. 22 depicts a structure
containing a number of microchannels connecting wells. Microfluidic
systems often require complex networks of wells and channels for
their operation. Such channels can be used to make multilayer
fluidic networks which include channels running in different
directions, transitioning between different heights, wells,
integrated valves, pumps, mixers, connectors and couplings, and so
on.
Electrochemical fabrication technology can be used to fabricate
tooling to enable a wide variety of industrial processes on a small
scale. Examples of such tooling are as follows:
Electrical Discharge Machining (EDM). Electrodes suitable for EDM
of various materials (including tool steels) can be made with
electrochemical fabrication technology, particularly from copper
and other electrodepositable elements and alloys that can be used
as structural material in electrochemical fabrication technology.
Materials with low erosion properties during EDM are preferred.
Tooling for EDM grinding and related processes can also be created
by co-depositing abrasive particles (e.g., diamond, silicon
carbide, boron carbide, aluminum oxide) along with metal.
Electrochemical Machining (ECM). Tooling suitable for ECM,
electrochemical deburring, shaped tube electrolytic machining, and
related means of processing a variety of materials can be made with
EFAB technology. Tooling for electrochemical grinding and similar
processes can also be created by co-depositing abrasive particles
(e.g., diamond, silicon carbide, boron carbide, aluminum oxide)
along with metal.
Electroplating. Anodes with special shapes intended to control
current distribution during plating, enhance plating within a
cavity, and so forth may be made with electrochemical fabrication
technology, for example, from copper, nickel, and platinum.
Ultrasonic machining. Tooling for ultrasonic machining of such
materials as carbides, ceramics, glass, and metals including
stainless steel can be made with electrochemical fabrication
technology. Tool life can be improved by co-depositing abrasive
particles (e.g., diamond, silicon carbide, boron carbide, aluminum
oxide) along with metal when fabricating the tool.
Injection and other molding. Tooling for injection, compression,
and transfer molding of components from polymers, mixtures of
polymers and metal (to fabricate metal injection molding preforms
via `metal injection molding`) or of polymers and ceramic (to
fabricate ceramic components via `ceramic injection molding`) can
be made with EFAB technology. Tooling can consist of multiple
elements which when combined form a cavity into which material is
introduced.
Blow and rotational molding. Tooling for blow molding and
rotational molding can be made with electrochemical fabrication
technology. Tooling can consist of multiple elements which when
combined form a cavity into which material is introduced.
Extrusion molding. Dies for extruding polymers, metals,
polymer/metal and polymer/ceramic mixtures (in which the polymer is
later removed and the metal or ceramic is sintered) can be made
with electrochemical fabrication technology.
Spinnerets--essentially extrusion dies for polymers used in the
fabrication of synthetic fiber--can similarly be fabricated. Due to
electrochemical fabrication technology's 3-dimensional nature,
semistreamlined and fully streamlined production dies can be
created, in which the die geometry is curved away from the extruded
structure on the exit side of the die. Dies designed to produce
hollow extrusions such as tubing and multi-lumen catheters for
medical applications--both featuring unusually small diameters--can
be produced.
Of particular interest is the fabrication of extrusion dies capable
of extruding multiple materials simultaneously to form a composite
structure. FIG. 23 shows a cross section of a coaxial extrusion die
designed to be fabricated with electrochemical fabrication
technology and which is capable of extruding up to three different
materials to form a coaxial composite extrudate such as that in
FIG. 24A. The design can be extended to more than three materials.
In FIG. 23, material is supplied through three separate inlets;
these can be on any desired face of the die. The edges on the exit
side of the die are preferably rounded to provide streamlining. The
inner dividing wall (which separates the center and inner material)
may be recessed below the outer dividing wall so as to allow the
center and inner materials to contact and fuse while the center
material is still supported by the outermost wall. Similarly, the
outer dividing wall (which separates the outer and center material)
may be recessed below the outermost wall so as to allow the outer
and center materials to contact and fuse while the outer material
is still supported by the outermost wall. Other configurations of
extrusion dies for multiple materials can, as shown in FIG. 24B,
produce extrudates in which two or more materials are surrounded by
a single material, or which combine the geometries of the
extrudates in both FIGS. 24A and 24B, as shown in FIG. 24C.
Thermoforming. Tooling for thermoforming of materials such as
thermoplastics can be made with electrochemical fabrication
technology. Vacuum applied through apertures in the forming surface
of the tool (FIG. 25) or air pressure applied to the opposite side
of the sheet of material to be formed, or both, can be used to form
the sheet over the shape of the tool. The tool in FIG. 25 shows how
a single vacuum manifold can connect all the vacuum holes in the
surface, and also illustrates flaring of the vacuum holes inwards
to enlarge them and promote etching of sacrificial material. Such
tooling can also be used to form ductile material supplied in thin
sheets, with or without heating or the use of vacuum or
pressure.
Die casting and permanent mold casting. Tooling for die casting and
permanent mold casting of metals, particularly those with
relatively low melting points (aluminum, magnesium, zinc, and of
course, indium, tin, Cerro metals, and solder) can be made using
electrochemical fabrication technology. Tooling can consist of
multiple elements which when combined form a cavity into which
material is introduced.
Metal forming. Tooling for drop forging and impact extrusion,
progressive die drawing, progressive roll forming, stretch-draw
forming, tube bending, tube and wire drawing, deep drawing, and
brake forming can be made with electrochemical fabrication
technology.
Powder metal and ceramic die pressing. Tooling for consolidating
metal and ceramic powders into preforms through pressure
and--optionally--heat, prior to sintering can be made with
electrochemical fabrication technology.
Machining. Tooling for broaching and fine blanking; gear hobbing
and gear shaping; lancing, shearing, and bending; nibbling and
notching; slitting; and punching, perforating and blanking can be
made with electrochemical fabrication technology. Taps and dies for
threading; drills, mills, files, lathe tools (e.g., for turning,
facing, and boring); and routing, shaping, and planing tools can
also be made with electrochemical fabrication technology.
Abrasive machining. Tooling for grinding, electrochemical grinding,
EDM grinding (as already mentioned), and honing can be produced
with EFAB technology. In addition, tooling for orbital grinding
(e.g., of graphite, but also of much harder materials) can be
fabricated in this way. Dicing saws for cutting semiconductor,
ceramic, and glass wafers can also be fabricated. All such tooling,
which relies on an abrasive action, can be made by co-depositing
abrasive particles (e.g., diamond, silicon carbide, boron carbide,
aluminum oxide) along with metal.
The hardness and wear resistance of all of the above tooling may be
made increased by co-depositing particles (e.g., diamond, silicon
carbide, boron carbide, aluminum oxide) along with
electrochemically-deposited metal. Alternatively, spray metal
deposition may be used to blanket deposit tool steel and other
structural materials desirable for tooling applications as the
structural material in electrochemical fabrication technology.
Since tooling often requires high strength, diffusion bonding of
the layers in tooling produced by electrochemical fabrication
technology may be carried out by heating the tooling to a
temperature which promotes diffusion across the layer interface.
This can be carried out either before or after removal of the
sacrificial material.
Tooling may also be fabricated indirectly--not as the direct result
of electrochemical fabrication technology, but for example, by
using an electrochemical fabrication technology-produced copper
electrode to electrical discharge machine tool steel which then
serves as the final tool.
Another Embodiment of the instant invention is shown in FIGS. 26A
and 26B. FIGS. 26A and 26B illustrate two different probe tip
configurations that may be used for probe cards or in other
electrical test environments. The probe electrodes 582 and 592,
respectively, are located within shields 584 and 594, respectively,
until the probe tip is approached at which point the shield is
allowed to drop away to allow contact between tips 586 and 596 with
pads to be tested. Probe cards are used to test and measure
integrated circuits during production. The move to higher
frequencies for these integrated circuits causes a higher demand to
be placed on the performance of probe cards. Further more as IC's
move to finer pitches, probes must be of smaller and finer pitch.
To improve operation of these probes at higher frequencies, it is
proposed herein and illustrated in FIGS. 26A and 26B that such
probes remain shielded (e.g. at ground potential) for as much of
the probe length as possible.
Another embodiment of the instant invention is illustrated in FIG.
27. FIG. 27 illustrates a pressure sensor whose movement is
controlled by a bellows like structure. The sensor consists of
moveable plate 602, fixed plate 604, bellows structure 606 and
dielectric 608 that separates plates 602 and bellows 606 from plate
604. As pressure changes, the bellows can extend or alternatively
can retract, thus changing the separation between plates 602 and
604 and changing an associated capacitance which can be detected
and correlated to a given pressure differential. The differential
being that between the pressure outside the sensor and the pressure
inside sealed area 612.
An additional embodiment of the invention is illustrated in FIGS.
28A-28D. FIG. 28A depicts a pair of capacitor plates 612 and 614
held apart by spacers 616 where extension rods 618 extend from
either side of the center of the capacitor by application of a
voltage differential between plate 612 and 614. The plates can be
made to attract one another and bend inward. Such bending will
cause displacement of extension rods 618 compressing their end to
end separation. Such a configuration may be used as an actuator.
Multiple such actuators can be combines together to form stacks
capable of more extensive end to end displacement. Appropriately
configured parallel configurations can be used to increase to
overall displacement force. A combination of series and parallel
configurations may also be useful. Such actuator combination, could
exert both greater force and increased displacement. A perspective
view of a single such actuator is shown in FIG. 29A where a
dielectric pad 622 is placed between the capacitor plates to
inhibit inadvertent shorting of them. FIG. 29B illustrates a
perspective view of three such stacked plates where electrical lead
lines 624(a), 624(b) and 624(c) extend along the sides of the
plates.
FIGS. 30A-30F illustrate some additional embodiments of the present
invention related to switches. FIG. 30A depicts a switch 702 that
includes a moveable beam 704 positioned between two actuation
plates 706 and 708. Movable member 704 includes a contact tip 712
which can be made to contact lead 714 when appropriately actuated.
This embodiment of FIG. 30A can use upper electrode 706 in addition
to any spring force associated with moveable member 704 to help
separate contactor 712 from lead 714. The embodiment of FIG. 30B
can be used in an analogous manner to that of 30A where an
additional contactor 718 is included which may be used to give the
switch a double throw capability. FIG. 30C illustrates another
switch embodiment that uses an electrode configuration 722 that is
at least partially conformed to the shape of moving member 724 when
moving member is deflected to contact element 726. FIG. 30D depicts
a double throw switch embodiment which includes contour electrodes
that at least partially mimic the shape of moving member 734 when
deflected to contact elements 736 or 738. FIG. 30F depicts another
alternative switch embodiment where a central electrode 744 is
activated to pull an upper moveable member 746 and a lower movable
member 748 together to make contact between elements 746 and 748.
FIGS. 31A-31C depict additional embodiments of the present
invention FIG. 31A depicts a beam 772 that is located above an
electrode 774 where the electrode has walls 776 that approach the
sides of beam 772. As a potential is placed between beam 772 and
electrode 774, beam 772 is attracted downward toward the electrode
where the attraction force is stronger then it would have been if
electrode 774 were just a flat plate. Side walls 776 do not inhibit
the motion of beam 772, but do lower the activation voltage
necessary to displace bean 772. The beam 772 may be a cantilever
beam supported at one end which is opposite to the end of the view
of FIG. 31A. Alternatively, beam 772 may be a spring loaded plate
that can move vertically up and down as apposed to undergoing a
bending motion. FIG. 31 B depicts a similar embodiment to that of
31A with the exception that an upper electrode 782 is depicted
which may be used to deflect the beam upward or to aid in pulling
or releasing the beam from a contact position when it is deflected
toward electrode 774. FIG. 31C shows an alternative embodiment
where a beam 784 can be deflected in any of four directions by
electrodes 786(a), 786(b), 786(c) or 786(d). As with some of the
other embodiments alternatives to the embodiments of FIGS. 31A-31C
may include dielectric stops, and the like, which may be helpful in
minimizing contact between the beam and the electrodes.
The patent applications in the following table are hereby
incorporated by reference herein as if set forth in full. The gist
of each patent application is included in the table to aid the
reader in finding specific types of teachings. It is not intended
that the incorporation of subject matter be limited to those topics
specifically indicated, but instead the incorporation is to include
all subject matter found in these applications. The teachings in
these incorporated applications can be combined with the teachings
of the instant application in many ways. For example, the various
apparatus configurations disclosed in these referenced applications
may be used in conjunction with the novel features of the instant
invention to provide various alternative apparatus that include the
functionality disclosed herein:
TABLE-US-00001 U.S. application No. Title Filing Date Brief
Description U.S. application No. 09/488,142 Method for
Electrochemical Fabrication Jan. 20, 2000 This application is a
divisional of the application that led to the above noted `630
patent. This application describes the basics of conformable
contact mask plating and electrochemical fabrication including
various alternative methods and apparatus for practicing EFAB as
well as various methods and apparatus for constructing conformable
contact masks U.S. application No. 09/755,985 Microcombustor and
Combustion-Based Thermoelectric Microgenerator Jan. 5, 2001
Describes a generally toroidal counterflow heat exchanger and
electric current microgenerator that can be formed using
electrochemical fabrication. U.S. application No. 60/379,136
Selective Electrochemical Deposition Methods Having Enhanced
Uniform May 7, 2002 Deposition Capabilities Describes conformable
contact mask processes for forming selective depositions of copper
using a copper pyrophosphate plating solution that allows
simultaneous deposition to at least one large area (greater than
about 1.44 mm.sup.2) and at least one small area (smaller than
about 0.05 mm.sup.2) wherein the thickness of deposition to the
smaller area is no less than one-half the deposition thickness to
the large area when the deposition to the large area is no less
than about 10 .mu.m in thickness and where the copper pyrophosphate
solution contains at least 30 g/L of copper. The conformable
contact mask process is particularly focused on an electrochemical
fabrication process for producing three-dimensional structures from
a plurality of adhered layers. U.S. application No. 60/379,131
Selective Electrodeposition Using Conformable Contact Masks Having
May 7, 2002 Enhanced Longevity Describes conformable contact masks
that include a support structure and a patterned elastomeric
material and treating the support structure with a corrosion
inhibitor prior to combining the support and the patterned
elastomeric material to improve the useful life of the mask. Also
describes operating the plating bath at a low temperature so as to
extend the life of the mask. U.S. application No. 60/379,132
Methods and Apparatus for Monitoring Deposition Quality During May
7, 2002 Conformable Contact Mask Plating Operations Describes an
electrochemical fabrication process and apparatus that includes
monitoring of at least one electrical parameter (e.g. voltage)
during selective deposition using conformable contact masks where
the monitored parameter is used to help determine the quality of
the deposition that was made. If the monitored parameter indicates
that a problem occurred with the deposition, various remedial
operations are undertaken to allow successful formation of the
structure to be completed. U.S. application No. 60/329,654
"Innovative Low-Cost Manufacturing Technology for High Aspect Ratio
Oct. 15, 2001 Microelectromechanical Systems (MEMS)" A conformable
contact masking technique where the depth of deposition is enhanced
by pulling the mask away from the substrate as deposition is
occurring in such away that the seal between the conformable
portion of the mask and the substrate shifts from the face of the
conformal material and the opposing face of the substrate to the
inside edges of the conformable material and the deposited
material. U.S. application No. 60/379,129 Conformable Contact
Masking Methods and Apparatus Utilizing In Situ May 7, 2002
Cathodic Activation of a Substrate An electrochemical fabrication
process benefiting from an in situ cathodic activation of nickel is
provided where prior to nickel deposition, the substrate is exposed
to the desired nickel plating solution and a current less than that
capable of causing deposition is applied through the plating
solution to the substrate (i.e. cathode) to cause activation of the
substrate, after which, without removing the substrate from the
plating bath, the current is increased to a level which causes
deposition to occur. U.S. application No. 60/379,134
Electrochemical Fabrication Methods With Enhanced Post Deposition
Processing May 7, 2002 An electrochemical fabrication process for
producing three-dimensional structures from a plurality of adhered
layers is provided where each layer includes at least one
structural material (e.g. nickel) and at least one sacrificial
material (i.e. copper) that will be etched away from the structural
material after the formation of all layers have been completed. A
copper etchant containing chlorite (e.g. Enthone C-38) is combined
with a corrosion inhibitor (e.g. sodium nitrate) to prevent pitting
of the structural material during removal of the sacrificial
material. U.S. application No. 60/364,261 Electrochemical
Fabrication Method and Apparatus for Producing Three- Mar. 13, 2002
Dimensional Structures Having Improved Surface Finish An
electrochemical fabrication (EFAB) process and apparatus are
provided that remove material deposited on at least one layer using
a first removal process that includes one or more operations having
one or more parameters, and remove material deposited on at least
one different layer using a second removal process that includes
one or more operations having one or more parameters, wherein the
first removal process differs from the second removal process by
inclusion of at least one different operation or at least one
different parameter. U.S. application No. 60/379,133 Method of and
Apparatus for Forming Three-Dimensional Structures Integral May 7,
2002 With Semiconductor Based Circuitry An electrochemical
fabrication (e.g. by EFAB .TM.) process and apparatus are provided
that can form three-dimensional multi-layer structures using
semiconductor based circuitry as a substrate. Electrically
functional portions of the structure are formed from structural
material (e.g. nickel) that adheres to contact pads of the circuit.
Aluminum contact pads and silicon structures are protected from
copper diffusion damage by application of appropriate barrier
layers. In some embodiments, nickel is applied to the aluminum
contact pad via solder bump formation techniques using electroless
nickel plating. U.S. application No. 60/379,176 Selective
Electrochemical Deposition Methods Using Pyrophosphate Copper May
7, 2002 Plating Baths Containing Citrate Salts An electrochemical
fabrication (e.g. by EFAB .TM.) process and apparatus are provided
that can form three-dimensional multi-layer structures using
pyrophosphate copper plating solutions that contain a citrate salt.
In preferred embodiments the citrate salts are provided in
concentrations that yield improved anode dissolution, reduced
formation of pinholes on the surface of deposits, reduced
likelihood of shorting between anode and cathode during deposition
processes, and reduced plating voltage throughout the period of
deposition. A preferred citrate salt is ammonium citrate in
concentrations ranging from somewhat more that about 10 g/L for 10
mA/cm.sup.2 current density to as high as 200 g/L or more for a
current density as high as 40 mA/cm.sup.2. U.S. application No.
60/379,135 Methods of and Apparatus for Molding Structures Using
Sacrificial Metal Patterns May 7, 2002 Molded structures, methods
of and apparatus for producing the molded structures are provided.
At least a portion of the surface features for the molds are formed
from multilayer electrochemically fabricated structures (e.g.
fabricated by the EFAB .TM. formation process), and typically
contain features having resolutions within the 1 to 100 .mu.m
range. The layered structure is combined with other mold
components, as necessary, and a molding material is injected into
the mold and hardened. The layered structure is removed (e.g. by
etching) along with any other mold components to yield the molded
article. In some embodiments portions of the layered structure
remain in the molded article and in other embodiments an additional
molding material is added after a partial or complete removal of
the layered structure. U.S. application No. 60/379,177
Electrochemically Fabricated Structures Having Dielectric Bases and
May 7, 2002 Methods of and Apparatus for Producing Such Structures
Multilayer structures are electrochemically fabricated (e.g. by
EFAB .TM.) on a temporary conductive substrate and are there after
are bonded to a permanent dielectric substrate and removed from the
temporary substrate. The structures are formed from top layer to
bottom layer, such that the bottom layer of the structure becomes
adhered to the permanent substrate. The permanent substrate may be
a solid sheet that is bonded (e.g. by an adhesive) to the layered
structure or the permanent substrate may be a flowable material
that is solidified adjacent to or partially surrounding a portion
of the structure with bonding occurs during solidification. The
multilayer structure may be released from a sacrificial material
prior to attaching the permanent substrate or more preferably it
may be released after attachment. U.S. application No. 60/379,182
Electrochemically Fabricated Hermetically Sealed Microstructures
and May 7, 2002 Methods of and Apparatus for Producing Such
Structures Multilayer structures are electrochemically fabricated
(e.g. by EFAB .TM.) from at least one structural material (e.g.
nickel), at least one sacrificial material (e.g. copper), and at
least one sealing material (e.g. solder). The layered structure is
made to have a desired configuration which is at least partially
and immediately surrounded by sacrificial material which is in turn
surrounded almost entirely by structural material. The surrounding
structural material includes openings in the surface through which
etchant can attack and remove trapped sacrificial material found
within. Sealing material is located near the openings. After
removal of the sacrificial material, the box is evacuated or filled
with a desired gas or liquid. Thereafter, the sealing material is
made to flow, seal the openings, and resolidify. U.S. application
No. TBD Electrochemically Fabricated Hermetically Sealed
Microstructures and Dkt No. P-U.S.021-B-MG Methods of and Apparatus
for Producing Such Structures Dec. 3, 2002. Multilayer structures
are electrochemically fabricated (e.g. by EFAB .TM.) from at least
one structural material (e.g. nickel), at least one sacrificial
material (e.g. copper), and at least one sealing material (e.g.
solder). The layered structure is made to have a desired
configuration which is at least partially and immediately
surrounded by sacrificial material which is in turn surrounded
almost entirely by structural material. The surrounding structural
material includes openings in the surface through which etchant can
attack and remove trapped sacrificial material found within.
Sealing material is located near the openings. After removal of the
sacrificial material, the box is evacuated or filled with a desired
gas or liquid. Thereafter, the sealing material is made to flow,
seal the openings, and resolidify. U.S. application No. 60/379,184
Multistep Release Method for Electrochemically Fabricated
Structures May 7, 2002 Multilayer structures are electrochemically
fabricated (e.g.
by EFAB .TM.) from at least one structural material (e.g. nickel),
that is configured to define a desired structure and which may be
attached to a support structure, and at least a first sacrificial
material (e.g. copper) that surrounds the desired structure, and at
least one more material which surrounds the first sacrificial
material and which will function as a second sacrificial material.
The second sacrificial material is removed by an etchant and/or
process that does not attack the first sacrificial material.
Intermediate post processing activities may occur, and then the
first sacrificial material is removed by an etchant or process that
does not attack the at least one structural material to complete
the release of the desired structure. U.S. application No.
60/392531 Miniature RF and Microwave Components and Methods for
Fabricating Such Components Jun. 27, 2002 RF and microwave
radiation directing or controlling components are provided that are
monolithic, that are formed from a plurality of electrodeposition
operations, that are formed from a plurality of deposited layers of
material, that include inductive and capacitive stubs or spokes
that short a central conductor of a coaxial component to the an
outer conductor of the component, that include non-radiation-entry
and non-radiation-exit channels that are useful in separating
sacrificial materials from structural materials and that are
useful, and/or that include surface ripples on the inside surfaces
of some radiation flow passages. Preferred formation processes use
electrochemical fabrication techniques (e.g. including selective
depositions, bulk depositions, etching operations and planarization
operations) and post- deposition processes (e.g. selective etching
operations and/or back filling operations). U.S. application No.
60/415,374 Monolithic Structures Including Alignment and/or
Retention Fixtures Oct. 1, 2002 for Accepting Components Permanent
or temporary alignment and/or retention structures for receiving
multiple components are provided. The structures are preferably
formed monolithically via a plurality of deposition operations
(e.g. electrodeposition operations). The structures typically
include two or more positioning fixtures that control or aid in the
positioning of components relative to one another, such features
may include (1) positioning guides or stops that fix or at least
partially limit the positioning of components in one or more
orientations or directions, (2) retention elements that hold
positioned components in desired orientations or locations, and (3)
positioning and/or retention elements that receive and hold
adjustment modules into which components can be fixed and which in
turn can be used for fine adjustments of position and/or
orientation of the components. U.S. application No. 10/271,574
Methods of and Apparatus for Making High Aspect Ratio Oct. 15, 2002
Microelectromechanical Structures Various embodiments of the
invention present techniques for forming structures (e.g.
HARMS-type structures) via an electrochemical extrusion (ELEX .TM.)
process. Preferred embodiments perform the extrusion processes via
depositions through anodeless conformable contact masks that are
initially pressed against substrates that are then progressively
pulled away or separated as the depositions thicken. A pattern of
deposition may vary over the course of deposition by including more
complex relative motion between the mask and the substrate
elements. Such complex motion may include rotational components or
translational motions having components that are not parallel to an
axis of separation. More complex structures may be formed by
combining the ELEX .TM. process with the selective deposition,
blanket deposition, planarization, etching, and multi-layer
operations of EFAB .TM.. U.S. application No. 60/422,008 EFAB
Methods and Apparatus Including Spray Metal Coating Processes Oct.
29, 2002 Various embodiments of the invention present techniques
for forming structures via a combined electrochemical fabrication
process and a thermal spraying process. In a first set of
embodiments, selective deposition occurs via conformable contact
masking processes and thermal spraying is used in blanket
deposition processes to fill in voids left by selective deposition
processes. In a second set of embodiments, selective deposition via
a conformable contact masking is used to lay down a first material
in a pattern that is similar to a net pattern that is to be
occupied by a sprayed metal. In these other embodiments a second
material is blanket deposited to fill in the voids left in the
first pattern, the two depositions are planarized to a common level
that may be somewhat greater than a desired layer thickness, the
first material is removed (e.g. by etching), and a third material
is sprayed into the voids left by the etching operation. The
resulting depositions in both the first and second sets of
embodiments are planarized to a desired layer thickness in
preparation for adding additional layers to form three-dimensional
structures from a plurality of adhered layers. In other
embodiments, additional materials may be used and different
processes may be used. U.S. application No. 60/422,007 Medical
Devices and EFAB Methods and Apparatus for Producing Them Oct. 29,
2002 Various embodiments of the invention present miniature medical
devices that may be formed totally or in part using electrochemical
fabrication techniques. Sample medical devices include
micro-tweezers or forceps, internally expandable stents, bifurcated
or side branch stents, drug eluting stents, micro- valves and
pumps, rotary ablation devices, electrical ablation devices (e.g.
RF devices), micro-staplers, ultrasound catheters, and fluid
filters. In some embodiments devices may be made out of a metal
material while in other embodiments they may be made from a
material (e.g. a polymer) that is molded from an electrochemically
fabricated mold. Structural materials may include gold, platinum,
silver, stainless steel, titanium or pyrolytic carbon- coated
materials such as nickel, copper, and the like. U.S. application
No. 60/422,982 Sensors and Actuators and Methods and Apparatus for
Producing Them Nov. 1, 2002 Various embodiments of the invention
present sensors or actuators that include a plurality of capacitor
(i.e. conductive) plates that can interact with one another to
change an electrical parameter that may be correlated to a physical
parameter such as pressure, movement, temperature, or the like or
that may be driven may an electrical signal to cause physical
movement. In some embodiments the sensors or actuators are formed
at least in part via electrochemical fabrication (e.g. EFAB). U.S.
application No. TBD Multi-cell Masks and Methods and Apparatus for
Using Such Masks To Form Dkt No. P-U.S.042-B-MG Three-Dimensional
Structures Nov. 26, 2002. Multilayer structures are
electrochemically fabricated via depositions of one or more
materials in a plurality of overlaying and adhered layers.
Selectivity of deposition is obtained via a multi-cell controllable
mask. Alternatively, net selective deposition is obtained via a
blanket deposition and a selective removal of material via a
multi-cell mask. Individual cells of the mask may contain
electrodes comprising depositable material or electrodes capable of
receiving etched material from a substrate. Alternatively,
individual cells may include passages that allow or inhibit ion
flow between a substrate and an external electrode and that include
electrodes or other control elements that can be used to
selectively allow or inhibit ion flow and thus inhibit significant
deposition or etching. U.S. application No. TBD Non-Conformable
Masks and Methods and Apparatus for Forming Three- Dkt No.
P-U.S.043-A-MG Dimensional Structures Nov. 26, 2002.
Electrochemical Fabrication may be used to form multilayer
structures (e.g. devices) from a plurality of overlaying and
adhered layers. Masks, that are independent of a substrate to be
operated on, are generally used to achieve selective patterning.
These masks may allow selective deposition of material onto the
substrate or they may allow selective etching of a substrate where
after the created voids may be filled with a selected material that
may be planarized to yield in effect a selective deposition of the
selected material. The mask may be used in a contact mode or in a
proximity mode. In the contact mode the mask and substrate
physically mate to form substantially independent process pockets.
In the proximity mode, the mask and substrate are positioned
sufficiently close to allow formation of reasonably independent
process pockets. In some embodiments, masks may have conformable
contact surfaces (i.e. surfaces with sufficient deformability that
they can substantially conform to surface of the substrate to form
a seal with it) or they may have semi-rigid or even rigid surfaces.
Post deposition etching operations may be performed to remove flash
deposits (thin undesired deposits). U.S. application No. TBD
Miniature RF and Microwave Components and Methods for Fabricating
Such Components Dkt No. P-U.S.044-A-MG RF and microwave radiation
directing or controlling components are Dec. 3, 2002. provided that
may be monolithic, that may be formed from a plurality of
electrodeposition operations and/or from a plurality of deposited
layers of material, that may include switches, inductors, antennae,
transmission lines, filters, and/or other active or passive
components. Components may include non-radiation-entry and
non-radiation-exit channels that are useful in separating
sacrificial materials from structural materials. Preferred
formation processes use electrochemical fabrication techniques
(e.g. including selective depositions, bulk depositions, etching
operations and planarization operations) and post-deposition
processes (e.g. selective etching operations and/or back filling
operations).
Additional material concerning microdevices and their fabrication
can be found in the following three books which are hereby
incorporated herein by reference as if set forth in full herein: 1.
Multiple authors, The MEMS Handbook, edited by Mohamed Gad-El-Hak,
CRC Press, 2002. 2. M. Madou, Fundamentals of Microfabrication, CRC
Press, 2002. 3. Multiple authors, Micromechanics and MEMS, edited
by William Trimmer, IEEE Press, 1997.
Various other embodiments of the present invention exist. Some of
these embodiments may be based on a combination of the teachings
herein with various teachings incorporated herein by reference.
Some embodiments may not use any blanket deposition process and/or
they may not use a planarization process. Some embodiments may
involve the selective deposition of a plurality of different
materials on a single layer or on different layers. Some
embodiments may use blanket deposition processes that are not
electrodeposition processes. Some embodiments may use selective
deposition processes on some layers that are not conformable
contact masking processes and are not even electrodeposition
processes. Some embodiments may use the non-conformable contact
mask or non-contact masking techniques set forth in the above
referenced U.S. Provisional Application corresponding to
P-US042-B-MG.
Some embodiments may use nickel as a structural material while
other embodiments may use different materials such as copper, gold,
silver, or any other electrodepositable materials that can be
separated from the a sacrificial material. Some embodiments may use
copper as the structural material with or without a sacrificial
material. Some embodiments may remove a sacrificial material while
other embodiments may not. In some embodiments the sacrificial
material may be removed by a chemical etching operation, an
electrochemical operation, or a melting operation. In some
embodiments the anode may be different from the conformable contact
mask support and the support may be a porous structure or other
perforated structure. Some embodiments may use multiple conformable
contact masks with different patterns so as to deposit different
selective patterns of material on different layers and/or on
different portions of a single layer. In some embodiments, the
depth of deposition will be enhanced by pulling the conformable
contact mask away from the substrate as deposition is occurring in
a manner that allows the seal between the conformable portion of
the CC mask and the substrate to shift from the face of the
conformal material to the inside edges of the conformable
material.
In view of the teachings herein, many further embodiments,
alternatives in design and uses of the instant invention will be
apparent to those of skill in the art. As such, it is not intended
that the invention be limited to the particular illustrative
embodiments, alternatives, and uses described above but instead
that it be solely limited by the claims presented hereafter.
* * * * *